In a Young's double-slit experiment , the slits are separated by `0.28` mm and screen is placed `1.4` m away . The distance between the central bright fringe and the fourth bright fringe is measured to be `1.2` cm . Determine the wavelength of light used in the experiment .

Options

A. `6xx10^(-7)m`
B. `3xx10^(-7)m`
C. `1.5xx10^(-7)m`
D. `5xx10^(-6)m`

Answer

A

Explanation

For constructive interference, `x=n lambda(D)/(d)`
Here, `n=4, d=0.28xx10^(-3)m ` and `D=1.4m`
` :. lambda=(xd)/(nD)=(1.2xx10^(-2)xx0.28xx10^(-3))/(4xx1.4)=6xx10^(-7)m`